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Is VLC 3.0.3 for Windows 7?



 
 
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  #21  
Old August 14th 18, 01:32 PM posted to alt.windows7.general,alt.comp.os.windows-10,alt.comp.hardware.pc-homebuilt,alt.comp.os.windows-10,sci.electronics.basics
NY
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Posts: 9
Default film vs CMOS

"Phil Hobbs" wrote in message
...
But why can't we use a bigger film then? Should we always compare 135
film against CMOS sensors of different size?


A bit of possibly useful discussion:

https://electrooptical.net/News/photographic-film/


One other factor to bear in mind: the depth of field varies with lens focal
length, not field of view of the subject. This means that if you take a
photo on 120 film and on 35 mm, with appropriate focal lengths of the two
lenses to give the same field of view of the subject in both cases, and use
the same aperture, the DOF will be less on the 120 photo than the 35 mm
photo. So if 80 mm gives a certain field of view on 120 and 50 mm gives the
same field of view (ie shows the same extent of the subject) on 50 mm, and
both lenses are at f 4 (and so both will use the same shutter speed for the
same speed of film), the 120 photo will have a shallower DOF. That is why it
is so difficult to get shallow DOF on a compact or phone camera, because the
lens is such a short focal length to suit the very small sensor, that almost
everything is in focus even at a wide aperture (and the lens might have more
artifacts and aberrations than the comparable lens that gives the same field
of view for a 35 mm camera). In all this, I'm talking about the field of
view of the *subject* - ie how much of the subject (wide/telephoto) is
included within the frame of film or the sensor.

This is why some drama TV programmes are shot on 16 mm or with a similar
size CMOS sensor, but with a 35 mm-format movie camera lens and an
intermediate ground-glass screen. This allows a shallower DOF to be achieved
for artistic reasons without having to open up the (16 mm format) lens to a
wider aperture which might show more lens flaws. The lens for 35 mm format
produces an image on the ground-glass screen that has a certain field of
view and depth of field which would be recorded on 35 mm film. The 16 mm
camera focuses that image (which is all at one plane) onto 16 mm film.

I wish I could find a URL that describes it, but I'm obviously not feeding
Google with the correct search keywords - a common problem I have.

  #22  
Old August 14th 18, 05:08 PM posted to alt.windows7.general,alt.comp.os.windows-10,alt.comp.hardware.pc-homebuilt,alt.comp.os.windows-10,sci.electronics.basics
nospam
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Posts: 130
Default film vs CMOS

In article , NY
wrote:

One other factor to bear in mind: the depth of field varies with lens focal
length, not field of view of the subject.


actually, it's aperture.

This means that if you take a
photo on 120 film and on 35 mm, with appropriate focal lengths of the two
lenses to give the same field of view of the subject in both cases, and use
the same aperture, the DOF will be less on the 120 photo than the 35 mm
photo.


nope. it will be identical for the same image quality.

So if 80 mm gives a certain field of view on 120 and 50 mm gives the
same field of view (ie shows the same extent of the subject) on 50 mm, and
both lenses are at f 4 (and so both will use the same shutter speed for the
same speed of film), the 120 photo will have a shallower DOF. That is why it
is so difficult to get shallow DOF on a compact or phone camera, because the
lens is such a short focal length to suit the very small sensor, that almost
everything is in focus even at a wide aperture (and the lens might have more
artifacts and aberrations than the comparable lens that gives the same field
of view for a 35 mm camera).


only because the lens on the cellphone can't open wide enough to match
the depth of field of the larger sensor camera.

however, the lens on larger sensor camera will likely be able stop down
to match the depth of field of the cellphone camera. some lenses might
not, but that's a physical lens limitation.
  #23  
Old August 14th 18, 11:36 PM posted to alt.windows7.general,alt.comp.os.windows-10,alt.comp.hardware.pc-homebuilt,alt.comp.os.windows-10,sci.electronics.basics
Eric Stevens
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Posts: 33
Default film vs CMOS

On Sun, 12 Aug 2018 00:54:04 +0800, "Mr. Man-wai Chang"
wrote:

On 8/12/2018 12:50 AM, nospam wrote:
In article , Mr. Man-wai
Chang wrote:


But how do you get a 100% TRUE lossless original? Using good, old
film-based cameras?


film is more lossy than digital.


I don't know much about photography films. And you might need to talk
about the size (length x width) as well as the resolution of the senors
and films!

But isn't film molecular level?


Not really. A film image is constructed of crystaline grains which are
far above molecules in size.
--

Regards,

Eric Stevens
  #24  
Old August 15th 18, 09:22 AM posted to alt.windows7.general,alt.comp.os.windows-10,alt.comp.hardware.pc-homebuilt,alt.comp.os.windows-10,sci.electronics.basics
NY
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Posts: 9
Default film vs CMOS

"nospam" wrote in message
...
This means that if you take a
photo on 120 film and on 35 mm, with appropriate focal lengths of the two
lenses to give the same field of view of the subject in both cases, and
use
the same aperture, the DOF will be less on the 120 photo than the 35 mm
photo.


nope. it will be identical for the same image quality.


So as long as film grain isn't the limiting issue, you should be able to
take a photo on 120 film with a lens that gives a certain field of view, and
then on 35 mm with a different lens that gives the same field of view, and
if you use the same aperture on both lenses, you shouldn't see a shallower
DOF on a print from the larger format negative?

That goes against everything I've ever learned about photography, and the
fringe benefit of using larger film (the main one being finer level of
detail for the same type of film).

I'll have to try taking comparison photos on my SLR and compact cameras, to
test it.

As I thought, the SLR photo has a shallower DOF than the compact, for same
aperture and comparable lens focal lengths to give same field of view in
both photos.

Nikon D90, 18-200 mm lens, set to 150 mm, 35 mm equivalent=225mm, f5.6,
image size 4288 x 2848 pixels

https://s22.postimg.cc/phiylnsnl/DSC_0151.jpg


Canon Powershot SX260HS, 4.5-90 mm lens, set to 34 mm, no 35 mm equivalent
stated, f5.6, image size 4000 x 2664

https://s22.postimg.cc/k6420pe81/IMG_1316.jpg

Both these are full frame, both focussed on the pins of the mains adaptor in
the centre of the picture. Both pictures taken from same position (ie same
distance to subject in foreground). Very similar image resolution.

  #25  
Old August 15th 18, 03:16 PM posted to alt.windows7.general,alt.comp.os.windows-10,alt.comp.hardware.pc-homebuilt,alt.comp.os.windows-10,sci.electronics.basics
nospam
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Posts: 130
Default film vs CMOS

In article , NY
wrote:

This means that if you take a
photo on 120 film and on 35 mm, with appropriate focal lengths of the two
lenses to give the same field of view of the subject in both cases, and
use
the same aperture, the DOF will be less on the 120 photo than the 35 mm
photo.


nope. it will be identical for the same image quality.


So as long as film grain isn't the limiting issue, you should be able to
take a photo on 120 film with a lens that gives a certain field of view, and
then on 35 mm with a different lens that gives the same field of view, and
if you use the same aperture on both lenses, you shouldn't see a shallower
DOF on a print from the larger format negative?


if you do that, then the image quality will be different, which means
other characteristics may also be different.

also, depth of field is a function of the physical aperture (not
f/stop), so if you use the same f/stop on both (for exposure purposes)
you're actually using a larger aperture on the longer focal length
lens, thus the difference you're seeing (along with the difference in
image quality from the larger format, which can't be ignored).

That goes against everything I've ever learned about photography,


it's a common myth.

and the
fringe benefit of using larger film (the main one being finer level of
detail for the same type of film).


in other words, different image quality.

this explains it exceptionally well:
http://www.clarkvision.com/articles/dof_myth/
A commonly cited advantage of smaller digital cameras is their
greater depth-of-field. This is incorrect.

The myth, simply stated, is: smaller digital cameras have a larger
depth-of-field than larger digital cameras.

The simple reason why the myth is incorrect is that depth of field is
set by aperture, focal length, and a criterion for spatial
resolution, and if one keeps aperture of the larger camera the same
as that in the smaller camera, the two cameras record the same image
with the same signal-to-noise ratio and the same depth of field with
the same exposure time. Below are details explaining why this is
true, and Figure 1 gives an example.
....
Given the identical photon noise, exposure time, enlargement size,
and number of pixels giving the same spatial resolution (i.e. the
same total image quality), digital cameras with different sized
sensors will produce images with identical depths-of-field. (This
assumes similar relative performance in the camera's electronics,
blur filters, and lenses.) The larger format camera will use a higher
f/ratio and an ISO equal to the ratio of the sensor sizes to achieve
that equality. If the scene is static enough that a longer exposure
time can be used, then the larger format camera will produce the same
depth-of-field images as the smaller format camera, but will collect
more photons and produce higher signal-to-noise images. Another way
to look at the problem, is the larger format camera could use an even
smaller aperture and a longer exposure to achieve a similar
signal-to-noise ratio image with greater depth of field than a
smaller format camera. Thus, the larger format camera has the
advantage for producing equal or better images with equal or better
depth-of-field as smaller format cameras.
  #26  
Old August 15th 18, 05:06 PM posted to alt.windows7.general,alt.comp.os.windows-10,alt.comp.hardware.pc-homebuilt,alt.comp.os.windows-10,sci.electronics.basics
NY
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Posts: 9
Default film vs CMOS

"nospam" wrote in message
...
That goes against everything I've ever learned about photography,


it's a common myth.

and the
fringe benefit of using larger film (the main one being finer level of
detail for the same type of film).


in other words, different image quality.


I hadn't appreciated that image quality affected DOF. So same lens, same
camera, same aperture (but different shutter speed) on very slow
fine-grained film and very fast coarse-grained film will produce different
DOF?

Well, well.

this explains it exceptionally well:
http://www.clarkvision.com/articles/dof_myth/
A commonly cited advantage of smaller digital cameras is their
greater depth-of-field. This is incorrect.


Interesting article. The reason for the myth is that we are comparing the
wrong things and keeping the wrong things constant in the comparison. The
longer lens needed to produce the same field of view on the camera with the
larger sensor needs to be stopped down further make the *absolute* aperture
the same as for the camera with a smaller sensor and correspondingly smaller
focal length to give same field of view. Comparing f5.6 on the longer lens
with f5.6 on the shorter lens is wrong in terms of DOF. Understood!

Of course, in practical photographic terms, we tends to constraint aperture
to *roughly* the same range of f numbers for any lens. A lens that is 10x as
long doesn't have apertures which are roughly 1/10 (in f number terms) - on
all lenses, they will always be around f2 - f16 give or take a couple of f
numbers either way. That's so the light-gathering abilities of the lenses
are comparable.

So a camera with a small sensor will have a lens that has usable apertures
in terms of light-gathering capabilities which equate to a camera with a
larger sensor and hence a longer lens that has much smaller apertures and
therefore needs much longer exposures if film speed / CMOS sensitivity is
the same.


So a smaller camera doesn't inherently produce a greater depth of field, but
when it used in the same conditions of image brightness and film speed, and
the need to avoid diffraction due to excessively small apertures, the
smaller camera's range of *available* apertures produce a greater DOF than
the *available* range of apertures on a longer lens on a larger camera.

In other words, it's the age-old difference between theory and practical
usability.

  #27  
Old August 15th 18, 05:32 PM posted to alt.windows7.general,alt.comp.os.windows-10,alt.comp.hardware.pc-homebuilt,alt.comp.os.windows-10,sci.electronics.basics
NY
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Posts: 9
Default film vs CMOS

"NY" wrote in message
o.uk...
Interesting article. The reason for the myth is that we are comparing the
wrong things and keeping the wrong things constant in the comparison. The
longer lens needed to produce the same field of view on the camera with
the larger sensor needs to be stopped down further make the *absolute*
aperture the same as for the camera with a smaller sensor and
correspondingly smaller focal length to give same field of view. Comparing
f5.6 on the longer lens with f5.6 on the shorter lens is wrong in terms of
DOF. Understood!


The only thing that I'll need to read a few more times is the issue of
number of photons. I can see that this affects how much light the
film/sensor receives and therefore the brightness of the image. But I can't
see how it has any effect on the DOF of that image which is a purely
optical, lens issue: a dim image and a bright image will still have the same
objects in sharp focus and the same objects blurred by some amount.

So if in some way you halve the number of photos reaching the sensor (by
making the aperture smaller, by using a neutral density or by dimming the
illumination of the subject) then as long as you make the sensor twice as
sensitive or double the exposure time then the recorded image will be the
same. Of these, only altering the aperture alters the DOF. As long as the
aperture doesn't change, you can change all the other parameters and as long
as you do so proportionally, the image will be identical, both in brightness
and in DOF.

To think of it another way, suppose you have two sensors which have pixels
which are same size. In one case, the pixels border each other, without any
space between them; in the other case the pixels are the same size but
spaced more widely.

Sensor 1
x x x
x x x
x x x

versus

Sensor 2
x x x

x x x

x x x

The pixel size (the x) is the same size. So the size of the buckets is the
same.

But if the pixels are spaced more widely, the sensor will be physically
larger and will need a longer lens to capture the same field of view (and so
will need a smaller f number to give the same absolute size of aperture and
hence DOF).

But if we replace Sensor 2 by the more normal situation where the pixels are
bigger although their spacing hasn't altered (Sensor 3), the same lens is
needed and for the same aperture the DOF will be the same. I presume...

Sensor 3

X X X

X X X

X X X

The spacing is the same but the pixel size has increased from x to X which
means the larger buckets can gather more pixels.


I'm still struggling to see how altering the "size of the buckets" has
affected the DOF, if the pitch of the buckets is the same.


My brain hurts. I'm probably over-thinking all this :-)

 




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